White Paper: What PDF Security options are available?

Transcription

1 White Paper: What PDF Security options are available? When choosing PDF security solutions there are several key questions to ask. However, there is no perfect and universal solution to all requirements, so please don t expect one! For example, if physical printing is permitted the end user can always scan in the printout and screens can be photographed, scanned or captured and used to create a new PDF without security enabled intelligent watermarking can help discourage and protect against this problem. Every protection scheme has its limitations, and the more sophisticated it is the more obtrusive and difficult it typically becomes for the end user, so there is always a trade-off between simplicity and security. In practice international copyright law is a publisher s main form of protection the best PDF security solutions strongly discourage abuse of copyright and protect against the most obvious forms of piracy and copyright abuse. Initially we pose 12 questions and provide brief answers. We also provide more details on the product and services options available from a range of providers, including those using Adobe software (some core services are no longer provided directly from Adobe, as they stopped offering these in 2011) and from ourselves: Please also see our PDF Publishing Blog for news and views on many aspects of publishing PDF files. For Adobe s security advisory notices (breaches of the Adobe PDF offerings and updates to try and fix these) see: - scroll down this page to see the notices for Adobe Digital Editions, Adobe Reader and Adobe Acrobat Some of our recent Blog items on PDF Publishing include: Adobe Reader print security is not secure Amazon Kindle as a secure PDF reader Screen capture protection VAT rules in Europe about to change for ebook sales Audio and Video usage with PDF files How big is the Global publishing business? How to catch the ebook pirates Secure PDF Printing Google Nexus a suitable device for reading PDFs and ebooks? Adobe and Drumlin PDF Watermarking static and dynamic watermarks How to edit your PDFs we review the Infix PDF editor Permissioning vs Authorization what are the differences? PDF with very large page sizes How to add bookmarks to a PDF file CONTENTS Question 1: Who will be the end users of your document(s)? Question 2: Do your PDF files need to be read on a wide range of devices, from PCs to Mac computers, portable devices and ebook readers? Question 3: Do your PDF files need to be printed on non-standard paper/with no scale distortion? Drumlin Security Ltd 20/01/2016 Page:1

2 Question 4: Do you need to protect your PDF files from being copied to another computer or user and then read? Question 5: Do you need to protect your PDF files in other ways, for example to prevent printing or to control the date and time the file is available? Question 6: Do you require a free or very low cost solution? Question 7: Do you require a multi-language or specific (non-english) language solution? Question 8: Do you have a large number of documents to secure and manage? Question 9: Do you require a tailored PDF reader and or service? Question 10: Should I publish using PDF or epub? Question 11: Should I publish PDFs offline or online, or both? Question 12: What is the difference between permissioning-based systems and authorization-based systems? Note: The opinions expressed in this document are personal and readers should carry out their own reviews and investigations before making decisions on PDF security. All trade names and trademarks of software and service suppliers, including those belonging to Drumlin Security, Adobe, LockLizard and FileOpen amongst others remain the exclusive property of these organizations Drumlin Security Ltd 20/01/2016 Page:2

3 Question 1: Who will be the end users of your document(s)? If the answer is third party corporate customers in larger organizations, then your choices are: a) use standard Adobe Acrobat to create PDFs with security features enabled, which will work almost everywhere (but see below for significant security problems with this approach), or b) use a web-based solution that displays PDFs as images or uses a flash-based or HTML5 viewer some standalone viewers can provide secure viewing but require separate installation and licensing (see Question 11 for more details), or c) ask customers in such corporates to use their own home/laptop/netbook/mobile computers with a proprietary secure PDF reader this is often a practical option, depending on the application area d) most corporate networks are Windows PC based with internet access controlled via firewalls and proxy servers. Software solutions that will work in this environment include the standard Adobe reader and software that includes support for modern proxy servers, which includes the Javelin for Windows reader from Drumlin Security. The new JavelinPro reader and Corporate service from Drumlin Security is specifically designed for this kind of environment, offering device registration and document security management without requiring an online connection If you issue standard Adobe-compatible PDFs, but add security features using Adobe Acrobat such as watermarking, password to open, and text copy restrictions, these will be readable by the intended end user in all cases. However, such protection mechanisms are not necessarily implemented by non-adobe readers (see Adobe Reader print security is not secure for a blog item on this question) and can be removed by widely available software (see There is also no protection against the PDF being forwarded to someone else - i.e. there is no digital rights management (DRM) system included to protect against such copying. Solutions from the Adobe partner, FileOpen, do provide extra security of the type most customers require, but still require additional software installation and their services are provided at considerable cost. Their security system has been broken (in the past) according to the blog page: but may be OK now. Adobe also offer their Adobe Content Server (ACS), typically via third party distributors such as Bluefire. If the answer is intra-corporate, smaller corporate users, or consumers and home-based business PCs, then a large range of options is available. For intra-corporate and smaller corporate use, solutions based on services and software from Drumlin Security are ideal. Drumlin Security s Javelin secure PDF readers are available for PC, Mac, ipad, iphone and Android devices, so deliver true cross-platform delivery with a single file format and full DRM-enabled protection. Alternative authorization procedures can be provided, based on commercial and technical requirements, e.g. for specific bespoke apps. Drumlin Security Ltd 20/01/2016 Page:3

4 Question 2: Do your PDF files need to be read on a wide range of devices, from PCs to Mac computers, portable devices and ebook readers? If the answer is yes then you will need to decide whether you can conveniently convert your PDF to the various formats required by the different platforms or whether to stick with PDF: a) for PCs, Mac computers, ipads, iphones, Android tablets (or similar devices), sticking with pure PDFs is possible and often desirable although they are not secure unless augmented in some way with extra facilities. Not all solutions are available for PC and Mac OS in fact often the providers of security systems for PDFs are PC/Windows only. For some applications the latest version of Adobe s epublishing product set may be appropriate. For more details see: and for ebooks, the Adobe digital editions offering may be appropriate: - several bookstores and Library services (e.g. NetLibrary) use Adobe Content Server as their main platform for selling PDFs and epub formatted docs with built-in security see for example, the ebooks.com website. Drumlin Security s Javelin PDF readers are one of the few full functionality PDF readers that are available across all major technology platforms, free, and providing full DRM-based security for PDF files. b) For hardware-based portable ebook readers, every one tends to be different although there are some common standards - notably epub and MOBI (or Amazon Kindle variants of MOBI, e.g. KF8). In general these do not handle complex formatted PDFs and embedded images in a satisfactory manner the only way to know is to test converting your PDF to one of these other formats and to view the result on the target device and/or a desktop emulator of that device. Many of these devices are currently greyscale, so cannot display color, although this is changing rapidly. Services like Lulu and Smashwords provide consolidated distribution for epub-based ebooks, but not for PDFs. The Amazon Kindle family of devices is designed for a specific file format (see the Kindle page for more details), although it will read standard PDFs also (without security). Protection against screen capture tools such as is not provided. The latest addition to Amazon s Kindle range is the Kindle Fire (various models) that run an amended version of Android, and hence the Javelin secure PDF reader can be used in this environment using manual installation. Proprietary ebook readers are moving towards Android as a common operating system platform, with Nook being a good example (and now Kindle Fire). PDFs may be read on such devices and products like Javelin for Android (available free from the Google App Store) runs extremely well on such devices and provides the DRM security that many publishers and training companies are looking for. c) Dynamically converting a PDF to HTML is possible. This is a good option now that HTML5 is widespread as it supports much richer content types and structuring, but it is still not a complete substitute for PDF. For samples of PDFs in HTML5 please see: d) converting a PDF to images (typically initially as TIF files, one per page) is standard in Adobe Acrobat and the pages can then be embedded in an viewer, such as Google Drumlin Security Ltd 20/01/2016 Page:4

5 Books viewer. These kind of systems also extract the text content and use this for searching and related functionality. In the case of the Google Books viewer, you can use this within an iframe on any web page with any PDF you already have on your webserver or simply via a URL (e.g. a link in an or on a web page). For more on such file conversions please see Question 11 Question 3: Do your PDF files need to be printed on non-standard paper/with no scale distortion? If the answer is yes, for example you need to print on very large sheets for architectural drawings, engineering drawings, or clothing patterns, you have two options: a) convert the large-format file to tiles of standard paper size, e.g. A4 or US Letter this facility is available in some PDF manipulation software, notably in Adobe Acrobat. Note that tiled documents need to be manually re-assembled once printed, so are best accompanied by a diagram and/or markup showing how the pages fit together and providing clear/large numbering of the pages. Note that for scale-specific printouts the PDF reader must be able to reproduce the scale correctly b) keep to standard Adobe PDF, without security, and permit the end user to take a copy of their file to a digital print shop for output on a large format printer such print shops do not generally accept formats other than standard PDF and some image formats. There is no doubt that the print functionality of the core Adobe Acrobat reader is the best (most flexible) available from any provider c) Provide an in-network print service for the files, managed to ensure your document security is maintained Question 4: Do you need to protect your PDF files from being copied to another computer or user and then read? If the answer is yes you need to use a system (software and service) that provides Digital Rights Management (DRM). A DRM service can be intra-corporate (i.e. you have your own, inhouse server and service) or provided as a service by a third party, e.g. Adobe or Amazon or Drumlin. Many ebook stores provide PDF files (and other file formats) with no DRM, so these do not provide copy protection. If web-based ebookstores offer DRM support for PDFs it tends to be based on the Adobe Content Server solution. A list of Solution Providers for the Adobe Content server is provided at: It is important to note that every solution that provides DRM support involves two key components: a) a PDF reader that is DRM aware and has built-in security features b) a network connection to the DRM service for enabling or authorizing the file that the end user wishes to read In addition, the DRM may require unique user and/or device details in order to offer user- or device-specific controls. Alternatively the DRM can provide a one-shot authorization, irrespective of user or device, which greatly simplifies the process for the end user but reduces the control and tracking information available to the publisher. Drumlin Security offers multiple solutions with DRM, both online and offline. Drumlin Security Ltd 20/01/2016 Page:5

6 Question 5: Do you need to protect your PDF files in other ways, for example to prevent printing or to control the date and time the file is available? If the answer is yes you have two choices: a) use the facilities provided for security in Adobe s standard PDF offering (Adobe Acrobat/Acrobat Pro can create and manage such files), including disabling the clipboard, password protecting the file, and disabling printing. Note that date/time protection is not provided via this standard mechanism. Also note that such facilities may be ignored by some PDF readers, thereby effectively removing any intended protection, and in many cases protection can be readily removed by widely available third party software (unless the latest/strongest security settings from Adobe are used), so this provides a disincentive rather than a strong solution. Also note that a secured PDF can still be copied and distributed, unless additional DRM protection is provided. b) use the facilities provided in a specialized PDF reader that supports such controls within a strongly encrypted framework. Note that readers such as Adobe s Digital editions and LockLizard s PDF reader (which is based on the Foxit reader) require installation and registration to use, which may lead to technical and support issues (assuming that it is permitted by the corporate body). Drumlin s offerings, based on the Javelin family of PDF readers, include protection against copying to the clipboard, screen capture, start and end date controls, elapsed time control (e.g. can be viewed for 3 days), a range of controls on printing, number of viewings and number of prints control, user-specific watermarking, usage tracking and several other features. Note that for screen capture protection the only real cross-platform option is intelligent watermarking. See our blog article on this issue for more details: Question 6: Do you require a free or low cost solution? If the answer is yes, then the use of a third party service and software is the main choice, unless you plan to develop your own solution set (which can be very expensive). However, there are a great many services and offerings, most of which operate on a subscription service basis and/or a commission basis to recover their costs and maintain and develop their services. Very few free services exist that are genuinely secure. Question 7: Do you require a multi-language or specific (non- English) language solution? If the answer is yes, then you need to choose a solution that is multi-language enabled. This means that (a) menus and messages are available in the language of your choice or selectable by the end user, and (b) the page display supports the character encoding and display mode appropriate for example, to support Japanese, Hebrew and Arabic, right-toleft page turning and text searching is required, which may not be available. Many pure PDF readers, such as those from Adobe, Foxit and Drumlin, do offer multi-language support. With Foxit and Drumlin the language files are downloadable and/or coded in XML format, so may be modified and/or new languages supported by end user translation of the English base file. Drumlin Security Ltd 20/01/2016 Page:6

7 The Javelin family of PDF readers support multiple languages (varying by platform). The Javelin for Windows readers provide support a wide range of languages. Question 8: Do you have a large number of documents to secure and manage? If the answer is yes, then you need to choose a solution that offers batch processing, especially if files may have to be updated on a regular basis (e.g. time expired files). If, in addition, a system for managing which files may be accessed by specific individuals or groups, a content management system (CMS) may be needed. There are many providers of CMS technology, and some PDF security solutions offer CMS-like functionality. Products like Adobe Acrobat Pro and Drumlin s PDF Reader/Publisher offer multi-file selection and publishing plus automated batch publishing of secure PDFs. Some systems, such as those from FileOpen and LockLizard, offer CMS-like facilities, but most offerings do not, leaving these facilities to be provided via established intra-corporate CMS implementations or in-network systems and services. Cross document text searching is a requirement in some situations, and currently this is only supported in the Adobe Acrobat suite, with indexes pre-built to support this form of search. Note that cross-document text search of encrypted files is not possible without a special external index file of text strings, because the secured documents cannot be searched directly by generic tools. Question 9: Do you require a tailored PDF reader and or service? If the answer is yes, you need to work with a third party supplier that permits tailoring and branding of their offerings. This is often referred to as white labelling. Suppliers, such as Drumlin Security, FileOpen and LockLizard are often happy to support in-house or third party development teams to implement tailored solutions that include components from their proprietary suites, and/or to offer managed services and client software that is branded and tailored. There are also a number of providers of PDF library software, i.e. toolkits (generally separate toolkits for each technology platform). These may be used to create branded PDF readers, or PDF reader facilities within other applications or services. Note that the licensing models for most such providers are often based on the number of end-user licenses issued that are based on these libraries and/or are restricted to use within a single app or application. In the latter case a separate license is required for each app and each platform. Question 10: Should I publish using PDF or epub? If your books are highly formatted and contain a lot of images, tables and similar formatted items, and you wish to retain these you will need to stick with the PDF format and/or create images from the pages which you can then publish online (rather like Google Books). This does restrict the range of devices to which you can effectively publish, owing to the limited size of such devices. On the other hand, the use of the epub format, which is XML based, provides for greater flexibility if you are looking for wide cross-device support and are not concerned about formatting, tables, images etc. The reason is that epub allows for re-formatting of the file on the fly, for example changing the size of text in order to make it more readable, and automatically re-flowing the text (so it is re-arranged on the page) to fit the display window offered by the device in question. Adobe Content Server digitally protects PDF and reflowable epub content for Adobe Digital Editions and supported mobile devices such as Sony s ebook reader. Drumlin Security Ltd 20/01/2016 Page:7

8 Question 11: Should I publish PDFs offline or online, or both? Let's start with the Online options There are any number of online services that will display PDFs converted to an alternative format (to flash or html5 nowadays, not to epub as PDF to epub rarely works!). Widely used for Magazines in "page flip" format, do they have a broader role? Examples: issuu (mainly for Magazines and brochures), Javelin online (our new secure online equivalent of our offline Javelin PDF readers), Scribd (a PDF book publishing platform - for mobile devices they now use an app instead), and Zyyne (a French-based service, similar to issuu). Google Play books display PDFs in some instances, but does so strictly as images (most Google Play books are in epub format and displayed online or offline using epub reader software). There are three main technology options for online PDF display (many services provide all 3, with an "adaptive" interface that selects the best option based on the device): 1. Convert the PDF to Adobe Flash. This is what many of the Magazine and brochure display services provide for desktops and laptops, often using a Flipbook-type display. See an example of flash-based PDF page display on our website here. (Guardian Newspaper sample) Advantages: Excellent display quality, good navigation, good printing functionality (if required, but not secure), fast and simple if implemented correctly Disadvantages: ipads and Android devices do not support Flash, so strictly for PCs and Macs, which must have a recent version of flash installed (most do). Long term support for Flash by Adobe is not planned. Not especially secure, but may be "good enough" for many applications. 2. Convert the PDF to HTML5. There has been an enormous amount of interest in HTML5 and how it could replace PDFs as the preferred display format. Files can be converted statically or dynamically - dynamic conversion is the norm. See examples on our website here. Advantages: Widespread support for HTML5 in all modern web browsers and the latest mobile devices; no requirement for software distribution or document distribution; fair to very good quality display and navigation; options for augmenting with multimedia (e.g. embedded video). Disadvantages: Not very secure (often no security provided), processor intensive (can be quite slow, especially for large documents unless cleverly split); not supported by some browsers (depends on when they were last updated). 3. Convert the file to pure HTML. Whilst this sounds like the least attractive option it forms part of most online PDF display solutions. In this case the PDF document is converted into images and is augmented by a text file generated from the source PDF that is then used for searching. Advantages: works on all devices, is quite fast even for large documents Drumlin Security Ltd 20/01/2016 Page:8

9 Disadvantages: requires pre-processing of the source PDF; is dependent on the resolution of the converted pages - typically 120dpi gives very good results but leads to larger stored page sizes. Almost all flipbook systems use page image records as a fallback solution. A big advantage of these systems is that they are simple to set up and manage, with all the data (documents, user-related data, tracking etc) kept centrally, and the building blocks are readily available at relatively low cost. Overall conclusion: excellent for applications such as magazines, some brochures/catalogs, and documents with large fonts and lots of graphics. Variable quality as a reading experience (particularly on mobile devices), other than for previews, limited browsing, searching and reading. Some offer pure PDF downloads as an option, so provide online and offline display, but generally without security. Now the Offline option There are several advantages to offline working, e.g. using a system like the Drumlin DRM service with Javelin PDF readers for the main technology platforms: PC, Mac, ipad and Android. Adobe and their DRM partners provide similar products and services. These include: instant access to the documents at all times, when continuous online connectivity is not possible or desired. This is particularly useful when travelling, in offsite locations, in training rooms, workshops, on board ships and aircraft etc the quality of the screen presentation is almost always better, as is the local functionality that can be provided (e.g. integration with catalogs, markup etc) speed of display and moving around the document is faster, and very large documents can be handled with ease (e.g pages) security can be far stronger than for online systems strict print control is possible (PC/Mac solutions), which is not practical for online systems The main disadvantage of an offline system is that it can require a bit more work from both the publisher and the end user. And there are occasionally situations where offline operation is not an option (e.g. where downloading and use of third party apps and/or secured documents is not permitted, e.g. due to corporate policy and security systems). These can often be worked around, either via onsite measures (approval of the app, enabling of proxy server support) or offsite measures (authorizing a file offsite/via open WiFi connectivity, using lincese-based authorization), or by using an online service as described above. Online or Offline? From the very brief summary above it is clear that there is a strong demand and widespread use of online PDF display, mainly in the "media" sector, with offline being the preferred route for documents that are designed to be read in detail and/or printed. There is also merit in combining the two, e.g.: enabling simple previews and promotions to be provided; allowing ancillary documents (e.g. promotional materials, videos etc) to be displayed; providing a subscription-based access service; and in addressing the security constraints that may apply for some sites. Drumlin Security Ltd 20/01/2016 Page:9

10 Question 12: What is the difference between permissioning-based systems and authorization-based systems? There are three main approaches that can be taken to provide digital rights management (DRM) for documents: 1. User-independent authorization systems: these are systems where files are downloaded and are authorised for offline usage by either: device identification, which requires prior registration of the device; or by entry of an authorisation code that is checked on a central DRM system (does not require prior registration). Note that with this second approach there is little or no requirement for central service management as the process is very largely automated. These are automated authorization based systems". Examples of device-based systems are Amazon Kindle, ipads with ibooks, and devices like Kobo and Nook. An example of a nondevice based authorization system (with no prior user registration) is the standard Drumlin service, with Javelin as the end-user reader. 2. User and/or device-dependent systems: these are systems where each person downloading a document must be pre-registered on a centrally managed service, and then each publication they are permitted to view is centrally enabled for them. These are permissioning based systems". Locklizard and the Drumlin Corporate option are examples of this kind of system, as is Microsoft s 365 online services. 3. Online-based systems: approaches 1 and 2 assume the files are to be downloaded and read offline - no host connectivity is required after the initial stage of downloading and enabling. In many ways a simpler alternative is a hosted service, where the files are kept centrally and displayed via a browser. A pure HTML or HTML5 based solution (with username/password login and other protective measures) would be an example of such a facility. Note that this option is very simple to manage because the files are held centrally, and access can be managed at the school or class level (with usage tracking) rather than at the individual student level (although the latter is entirely possible - just a bit more work administratively). The compromises here are: (i) the files can only be viewed online; (ii) access is controlled via permissioning, so requires manual management; (iii) the quality of display is typically not as good as offline PDF readers; (iv) the security is not as strong; (v) if printing is required, offline or in-network printing are the only safe options. READ MORE ABOUT ONLINE AND OFFLINE PRODUCTS AND SERVICES FROM US Drumlin Security Ltd 20/01/2016 Page:10